ET or not ET? Water and life on Mars

New and convincing evidence of what scientists say could be flowing liquid water on the surface of Mars, today, is reported in a paper published in this week’s Science magazine. Space scientists have been “following the water” on Mars and elsewhere in space because water is a key requirement for life (at least as we know it), and this new evidence looks persuasive.

As reported in Science, the Mars Reconnaissance Orbiter’s observations of the surface of the planet over several years has yielded evidence of small streams of liquid water waxing and waning from summer to winter, as surface temperatures rise and fall. At yesterday’s NASA press conference on the findings, Indiana University biogeochemist Lisa Pratt, who studies deep-subsurface microbial life on Earth, explained how microbial life, past or present, might live deep beneath the surface of Mars and perhaps even migrate to the surface when liquid water is/was present.

NASA’s August 3 media advisory about yesterday’s press conference promised “a significant new Mars science finding… based on observations from NASA’s Mars Reconnaissance Orbiter (MRO), which has been orbiting the Red Planet since 2006.” Science magazine had distributed this paper to the media in advance, embargoed until August 4.

The lead of NASA’s August 4 press release about the finding, headlined “NASA Spacecraft Data Suggest Water Flowing On Mars,” stated: “Observations from NASA’s Mars Reconnaissance Orbiter (MRO) have revealed possible flowing water during the warmest months on Mars. ‘NASA’s Mars Exploration Program keeps bringing us closer to determining whether the Red Planet could harbor life in some form,’ NASA Administrator Charles Bolden said, ‘and it reaffirms Mars as an important future destination for human exploration.’”

While the proceedings of NASA’s press conference focused on explaining the evidence for current, flowing liquid water on Mars, panelists also discussed the implications of these new findings for the search for evidence of past or present life on Mars.

Compare this science story with the story of the (now infamous) arsenic-life paper. On November 28, Science magazine distributed a paper to the media reporting the discovery of a (terrestrial) microbe that could substitute arsenic for phosphorus in its major macromolecules. The paper was embargoed until December 2, its online publication date. On November 29, NASA issued a media advisory about a briefing to report on this finding: “NASA Sets News Conference on Astrobiology Discovery; Science Journal Has Embargoed Details Until 2 p.m. EST On Dec. 2.” The media advisory stated: “NASA will hold a news conference at 2 p.m. EST on Thursday, Dec. 2, to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life. Astrobiology is the study of the origin, evolution, distribution and future of life in the universe.”

The online (and conventional) media environment – especially the blogosphere – teemed with speculation about the December 2 announcement. Somehow the far-fetched and, of course, erroneous idea that NASA had found evidence of extraterrestrial life, either in an extraterrestrial environment or on Earth, gained traction. (I’m now studying this phenomenon to better understand what happened, and how and why.) Some speculators responded to the actual news with disappointment. Many journalists accused NASA of “hyping” the news, pointing a finger at the agency’s statement that the finding reported on December 2 “will impact the search for evidence of extraterrestrial life.” (There’s much more to this story, but I won’t go into it here. I will, later.…)

NASA’s December 2 press release, headlined “NASA-Funded Research Discovers Life Built With Toxic Chemical,” led off: “NASA-funded astrobiology research has changed the fundamental knowledge about what comprises all known life on Earth. Researchers conducting tests in the harsh environment of Mono Lake in California have discovered the first known microorganism on Earth able to thrive and reproduce using the toxic chemical arsenic. The microorganism substitutes arsenic for phosphorus in its cell components…. This finding of an alternative biochemistry makeup will alter biology textbooks and expand the scope of the search for life beyond Earth.”

Regarding yesterday’s Mars news, neither NASA’s August 3 media advisory nor its August 4 press release nor its press-conference panelists used the word “extraterrestrial.” However, NASA’s press release and the press-conference panelists did link the new evidence to the search for life on Mars. (See above.)

Both of these science news stories relate to the ongoing scientific search for evidence of extraterrestrial (literally, “outside Earth”) habitability and life. How are the stories different?

First, the December 2 announcement reported on research funded by NASA’s astrobiology program, which fosters the study of the origin, evolution, and distribution of life in the universe. The astrobiology program is a research and analysis program, and while it funds work that contributes to missions, it does not fund missions. The August 4 announcement reported on research sponsored by NASA’s Mars exploration program, which funds missions (such as MRO) as well as research. (By the way, NASA’s lead scientist for Mars exploration describes the agency’s next mission to Mars, the Mars Science Laboratory (MSL), as “NASA’s first astrobiology mission to Mars since Viking.” NASA’s senior scientist for astrobiology also serves as deputy program scientist for MSL.)

Second, the December 2 announcement involved laboratory experimentation and complex chemistry. The August 4 announcement involved observations of the surface of Mars. A picture is worth a thousand words, and, for different reasons, scientists and non-scientists have come to trust (believe?) planetary imagery. We can see those streaks of what might be liquid water appearing and disappearing as the seasons change on Mars. We can’t see how GFAJ-1, the alleged arsenic-loving microbe, substitutes arsenic for phosphorus in its major macromolecules. We can watch a graphic animation of the process, but we know it’s not real. We can look at charts and graphs, but they don’t translate into a mental picture.

Third, the lead author of the arsenic-life paper was a young scientist, a postdoctoral researcher in the media spotlight for the first time. The lead author of the Mars-water paper was an experienced NASA investigator and a veteran of many media briefings relating to Mars exploration.

These two cases are different in other ways, but I’ll stop here. My observation for today is that yesterday’s media event, and coverage of that event thus far, shows that scientists and journalists can talk about the ongoing search for evidence of extraterrestrial life without having the conversation spin out of control.

As the Coffee Lady* used to say, “Discuss.”

*For those who are too young to remember Mike Myers’ “Coffee Talks” on Saturday Night Life, all I can say is, you poor things….




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